Cash app never asks to enter a mobile number to make any transaction. They will give more options to make your transaction easier. Even, it is easier to use on your smartphone, because you can access it from anywhere anytime. If you want your money back, then go to that payment and make a request for a refund. Even, you can get Cash app without phone number to resolve your all queries. https://www.email-contactsupport.com/cash-app-customer-service-number/